Fluorine-containing polyurethane polymers



United States Patent 3,413,271 FLUORlNE-CONTAINING POLYURETHANE POLYMERSWilliam E. Weesner, Kettering, Ohio, assignor to Monsanto ResearchCorporation, St. Louis, Mo., a corporation of Delaware No Drawing.Original application Apr. 28, 1966, Ser. No. 545,856, now Patent No.3,330,872, dated July 11, 1967. Divided and this application Oct. 31,1966, Ser. No.

1 Claim. (11. 260-775) ABSTRACT OF THE DISCLOSURE The specificationdiscloses polyurethanes prepared from organic diisocyanates and novelfluorine-containing hemiketals. The polyurethanes are useful asfunctional fluids for hydraulic systems, or as lubricants. Foamedpolyurethanes are also disclosed.

wherein R is selected from the class consisting of hydrofen andfluorine; R is selected from the class consisting of hydrogen, fluorinealkyl and fluorine-substituted alkyl radicals; Y is selected from theclass consisting of hydrocarbyl and halogen-substituted hydrocarbylradicals; and n is an integer of from 1 to 8.

Whether a mouo-hemiketal or a bis-hemikctal is obtained depends upon theproportion of the fluoroketone to the glycol as shown by the aboveequations.

The compounds provided by this invention therefore may be represented bythe formula 3,413,271 Patented Nov. 26, 1968 wherein Z is selected fromthe class consisting of hydrogen and and n is an integer of from 1 to 8.

Presently useful fiuoroketones are:

1,3-difluoro-2-propanone 1,1,3,3-tetrafluoro-2-propanonel,1,1,3,3-hexafluoro-2-propanone 2,4-difiuoro-3-pentanone1,l,1,2,2,4,4,5,5,5-decafluoro-3-pentanone Presently useful glycols are:

1,4-butanediol 1,5-pentanediol 1,8-octanediol 1,1 O-decanediol2,3dibromo-1,4-butanediol 2,2,3,3-tetrachloro-1,4-butanediol2,2,3,3,4,4-hexatluoro-1,5-pentanediol 2,5-dibromo-1,6-hexanediol2,3,4,5-tetrachloro-1,6-hexanediol 3,4-diiodo-1,6-hexanediol2,2,3,3,4,4,5,5-octafiuoro-1,6-hexanediol2,3,4,5,6,7,8-heptachloro-1,9-nonanediol 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9hexadecafiuoro 1,10 decanediol p-xylenediol Reaction of the fiuoroketonewith a glycol to give the presently provided fluorine-containinghemiketals is conducted by simply mixing the two reactants in a suitablesolvent until formation of said hemiketal is completed. As

' solvent there may be used benzene, toluene, xylene, etc.

The formation of mono-hemiketals takes place by reaction of one mole ofthe fiuoroketone with one mole of the glycol. A deficiency of thefiuoroketone may be employed, however, without deleterious results; theexcess glycol is readily separated from the product at the conclusion ofthe reaction. The formation of his hemiketals takes place by reaction oftwo moles of the fiuoroketone with one mole of the glycol. An excess ofthe fluoroketone may be employed if desired. When a ratio of between 1:1and 2:1 moles of fiuoroketone to glycol is employed, the productconsists of a mixture of the mono and bis hemiketals which may beseparated by any of several methods including distillation, solventextraction, chromatography, etc.

Generally the reaction is exothermic; hence, heating is usually notrequired and the reaction may be conducted by operating at ambienttemperatures, or even with cooling. However, to shorten the reactiontime and to achieve maximum production for a given size reaction vessel,it may be desirable to supply heat. Temperatures of from, say, 30 C. toC. are thus useful.

The reaction may either be conducted at atmospheric pressure, as bybubbling the fiuoroketone through the glycol or by contacting thegaseous and liquid reactants with vigorous stirring, or may be conductedat pressures greater than atmospheric in a suitable pressurized vesselpreferably provided with a shaking or stirring mechanism.

Catalysts may be employed to hasten the reaction between thefiuoroketone and the glycol, and for this purpose acids are useful.Thus, there may be used phosphoric acid, p-toluenesulfonic acid, etc.

The fluorine-containing hemiketals are generally liquids which areusually soluble in organic solvents such as benzene, dimethylformamide,etc.

BEST COPY The present hemiketals are useful as solvents, humectants, andchemical intermediates. By virtue of their terminal hydroxy groups theymay be further esterified with organic acids, acyl halides or acidanhydrides, e.g., to

wherein R, R, Y and n are as defined above and R' is O hydrocarbyl.

By reaction with alkylating reagents, e.g., diazomethane or dimethylsulfate, alkoxy ethers may be obtained. e.g.,

ITICO where R, R, Y and n are as defined above and m and p are integersof from 1 to 20.

Depending upon the ratio of hemiketal to diisocyanate employed, thepolymer may have predominately terminal hydroxy groups or terminalisocyanate groups, or may have both hydroxy and isocyanate groups.Mixtures of the hemiketals may be employed, as for example, the crudemixture obtained from the reaction of hexafiuoroacetone with a glycolwithout further separation. The polymers so obtained are useful asfunctional fluids for hydraulic systems or as lubricants. By virtue oftheir fluorine content they have relatively low flammability.

The invention is further illustrated by, but not limited to, thefollowing examples.

EXAMPLE 1 This example illustrates the preparation of a bis-hemiketalfrom 1,6-hexanediol.

A slurry of 23.6 g. (0.2 mole) of 1,6-hexanediol, 0.3 g.p-toluenesulfonic acid monohydrate and 500 ml. of benzene was warmed at50 C. This gave two liquid phases as the diol did not completelydissolve. Hexafluoroacetone was then bubbled in over 7.5 hours at 5051C. A clear solution resulted after 3 hours. The weight gain was 65.2 g.(0.392 mole as hexafluoroacetone). The ptoluenesulfonic acid wasneutralized with 0.2 g. sodium bicarbonate. Benzene was removed underreduced pressure at 4345 C. leaving 89 g. of bis-hemiketal as a liquidresidue.

EXAMPLE2 Percent Found Caled. for CiI-I F O4 C 23 .61 24 .28 II 1 .35 1.11 1" 63 .06 G2 .85

This then, establishes that the product was l,l,9,9-tetrakis(trifluorornethyl) 2,8 dioxa4,4,5,5,6,6-hexafluoro-1,9-nonanediol.

EXAMPLE 3 This example illustrates the preparation of a polyurethanepolymer having predominately terminal hydroxy groups.

A solution of 20.5 g. of the product from the reaction of 1,6-hexanedioland hexafluoroacetone, consisting essentially of a 5050 mixture of themono-and bis-hemiketals, in 75 ml. of dimethylformamide was treated with8.0 g. of 2,4-tolylene diisocyanate over 8 minutes at 2930 C. Thissolution stood at room temperature under nitrogen for 65 hours and wasthen heated at 3840 C. for 24 hours. An additional 1.2 g. of toluenediisocyanate was added and heating done at 42 C. for 26 hours longer.Then 0.1 ml. of water was added and heating continued at 42 C. for 2hours longer. Solvent was removed under reduced pressure at 4850 C.,leaving the product as a yellow, very viscous liquid, 27.5 g. Infraredspectroscopic analysis showed the absence of isocyanate groups. Theliquid polyurethane product was useful as a functional fluid and had arelatively low flammability.

EXAMPLE 4 This example illustrates the preparation of a polyurethanepolymer having both hydroxy and isocyanate groups as terminal groups.

A solution of the bis-hemiketal obtained in Example 2 is reacted indimethylformamide with a substantially stoichiometrically equivalentamount of 2,4-tolylene diisocyanate at about 30 C. for 65 hours and thenat about 40 C. for 24 hours. Solvent is removed under reduced pressure,leaving the polyurethane polymer as a viscous liquid having both hydroxyand isocyanate groups as terminal groups.

The polymer is useful for forming tough, well-bonded coatings, and maybe cured by reaction with atmospheric moisture. The polymer is shown tohave elastorneric properties.

EXAMPLE 5 This example illustrates the preparation of a polyurethanepolymer having predominately terminal isocyanate groups.

A solution of the bis-hemiketal obtained in Example 2 is reacted indimethylformamide with excess 2,4-to1ylenediisocyanate. The reaction isfirst conducted at about 30 C. for 60 hours, then at about 45 C. for 30hours. Solvent is removed under reduced pressure, leaving thepolyurethane polymer as a vicous liquid having predominately isocyanateend groups. A foam is obtained -by adding a foaming agent, e.g., water,together with a surface active agent, amine catalyst and plasticizer.

It is to be understood that although the invention has been describedwith a specific reference to particular embodiments thereof, it is notto be so limited since changes and alterations therein may be made whichare within the full intended scope of this invention as defined by theappended claim.

What is claimed is:

1. A polymer consisting of the repeating unit References Cited UNITEDSTATES PATENTS 2,911,390 11/1959 Smith 260-77.5 3,330,872 7/ 1967Weesner 260-615 FOREIGN PATENTS 994,411 6/ 1965 Great Britain.

DONALD E. CZAJA, Primary Examin r. FRED E. MCKELVEY, Assistant Examiner.

